SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function equals (children 1)
     ExpressionList (children 2)
      Literal NULL
      Function CAST (children 1)
       ExpressionList (children 2)
        Function toUInt8 (children 1)
         ExpressionList (children 1)
          Literal UInt64_0
        Literal \'Nullable(UInt8)\'